The Magnus effect was first publicized by Professor G. Magnus in 1853. The phenomenon is well-known in various arts including the curved pitches of baseball and the shooting of airplane guns transversely to the airplane's path of travel. The use of the Magnus effect as a rudder for a boat was disclosed in 1929 in U.S. Pat. No. 1,697,779. Other patents disclose the use of the Magnus effect for airplane lift and other use for assisting in submarine steering. Briefly stated, when a rotating cylinder encounters a fluid flow at an angle to its rotational axis, a lifting force is created perpendicularly to the flow direction. If a rotating cylinder is mounted on a vertical axis, a force is developed at right angles to the direction of water flowing past the cylinder, left or right depending upon the direction of rotation. The Magnus effect is therefore ideal for rudders for boats.
The control of Magnus effect rudders for boats and other watercraft has not heretofore been developed on an efficient basis, that is, obtaining the maximum amount of steering for a given expenditure of energy to rotate the Magnus cylinder.